I've been using a custom RailsCasts-derived (no red!) color scheme for many years, here's a version for VS: https://studiostyl.es/schemes/kodkod
It may be a double-edged sword though; I'm now looking at Solarized with a much more critical eye.
I've been using a custom RailsCasts-derived (no red!) color scheme for many years, here's a version for VS: https://studiostyl.es/schemes/kodkod